The Annals of Thoracic Surgery, Vol 37, 141-146, Copyright © 1984 by The Society of Thoracic Surgeons
Effects of oral amiodarone on left ventricular function in dogs: clinical implications for patients with life-threatening ventricular tachycardia
R Landymore, A Marble, G MacKinnon, R Leadon and M Gardner
Twenty-four mongrel dogs were divided into two equal groups to determine
the effects of orally administered amiodarone on left ventricular function.
Measurements of left ventricular function included left ventricular
contractility as denoted by maximum rate of rise of left ventricular
pressure (dP/dtmax), cardiac index (CI), left ventricular stroke work index
(LVSWI), and peripheral vascular resistance (PVR). Left ventricular
function was measured in 6 of the 12 animals in Group 1 before and after 14
days of amiodarone administered orally; the remaining animals served as
controls. The dP/dtmax was reduced from 2,855 to 1,291 mm Hg/sec (p less
than 0.01), and LVSWI fell from 1.6 to 0.74 gm-m/beat/kg (p less than 0.05)
in the 6 animals given amiodarone. The 12 animals in Group 2 underwent 30
minutes of ischemic arrest. Six animals in Group 2 underwent 30 minutes of
ischemic arrest. Six animals were given amiodarone orally for 14 days prior
to cardiopulmonary bypass and ischemic arrest; the other 6 served as
controls. Before cardiopulmonary bypass, the dogs administered amiodarone
had significantly greater depression of dP/dtmax (p less than 0.01) and
LVSWI (p less than 0.05). Thirty minutes of ischemia produced significant
depression of left ventricular function in all animals in Group 2. However,
a significantly greater reduction in dP/dtmax and LVSWI occurred in those
animals receiving amiodarone. Furthermore, 4 of the 6 dogs receiving
amiodarone were unable to sustain sufficient cardiac output following
cardiopulmonary bypass to permit long-term survival (p less than
0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
